Tires? Transmission? Intake/Exhaust?

I was driving on the highway and I start to notice a loud humm and feel vibration all around the cabin. With the windows up and the A/C on Econ with the fan blowing low, I could swear my car sounds like a rice burner with a fart can, just not as high pitched. It's not as bad / negligible when I'm going under 30 MPH but once I hit around 40 - 55, I hear it. And it's pretty loud. It's enough to drown out a conversation at regular speaking volume. Any one have any idea what's going on?

I accelerated to about 30 then put it on neutral and it's still there so I'm thinking it's not my engine. I also tried revving my engine in the parking lot later on and I didn't hear anything unusual.

My tires are somewhat worn, I just rotated them so the 2 worn out tires are in the back. I also recently got an oil change.


Any ideas would be appreciated. Thanks all.

 

Probably tire noise. The more your tires wear the more noise you will get from them.

 

I am not saying this is it BUT....I had a similiar thing happen to me. A vibration or shudder when driving. It could be felt in the steering wheel...basically the whole car would shake. It would come and go depending on revs. This would happen under acceleration or coasting down a hill. Turned out to be a bad driveline/axle. I just got my car back from the shop on Tuesday....new parts (no remanufactured stuff) $700. My 225 has 55k on the dial.